For your health — what to know about GLP-1 drugs for weight loss and health

By Dr. Graham A. Colditz, Siteman Cancer Center

As many of us know, keeping weight in check can be hard. And national numbers certainly reflect this. Rates of overweight and obesity in the U.S. have steadily climbed since the early 1980s.

The impact this has had on health and well-being is very significant. Weight gain and obesity increase the risk of 13 cancers, diabetes, stroke, arthritis, mobility problems and many other serious conditions.

So, the recent rise of GLP-1 medications for weight loss has become a promising bright spot.

Officially known as glucagon-like peptide-1 receptor agonists, GLP-1 drugs were first approved to treat type 2 diabetes — and later for weight management. The most commonly used GLP-1 drugs are semaglutide, sold as Ozempic or Wegovy, and tirzepatide (a dual GIP/GLP-1 receptor agonist), sold as Zepbound. They’re usually given with a once-a-week self-injection, but a semaglutide pill recently became available.

“GLP-1 receptor agonists are based on hormones that are made naturally by the body when we eat,” said Dr. Cynthia Herrick, a professor in the Division of Endocrinology, Metabolism and Lipid Research at WashU Medicine. “They slow the movement of food through the gut and have a complex effect on signals of fullness in the brain.”

In response, people eat less — and lose weight. Those using the most common once-a-week GLP-1 drugs have been shown in studies to lose around 15% to 20% of their body weight. 

On top of weight loss, studies have found a wide range of health benefits with GLP-1 drugs, which can vary depending on the specific drug. Herrick said they can help treat type 2 diabetes, prevent future heart attacks and stroke in people who have had them in the past, and lessen certain liver and kidney conditions. “The newest once-weekly drug, tirzepatide, has also been approved to treat moderate to severe sleep apnea,” Herrick added.

As with any medication, though, there can be downsides. Serious side effects are rare but can include gallstones, an inflamed pancreas and problems with food moving through the digestive system. There is also some concern that GLP-1 drugs may increase the risk of thyroid cancer, but so far, studies haven’t shown this.

More common side effects include nausea, occasional vomiting, bloating, mild diarrhea and constipation. To help minimize these, people are started on low doses, which are then increased monthly, Herrick said.

Since research on these drugs is still relatively young, it will take some time before we have more complete information about their long-term safety and benefits.

In addition to diabetes, GLP-1 drugs are most commonly prescribed for weight loss for people with a body mass index, or BMI, of 30 or higher, or a BMI of 27 or higher who also have a related condition, like high blood pressure or unhealthy blood cholesterol. Someone who is 5 feet 6 inches and weighs 186 pounds would have a BMI of 30, for example.

Insurance coverage for GLP-1 drugs can vary. Most plans will cover a GLP-1 drug to treat diabetes. But they’re less commonly covered for weight loss or other approved conditions. And even with insurance, monthly costs on some plans can be over $1,000 until people reach their deductibles.

Some options, though, can help. “There are now direct-to-consumer programs from the pharmaceutical companies that can lower the cost to $150 to $450 per month, depending on the medication and dose,” Herrick said.

Since people on GLP-1 therapy will likely be on it long-term, affordable access can be especially important. “I tell people to think of these the way we think of blood pressure and cholesterol medicines,” Herrick said. “These work to reduce heart disease risk, but only when taking the medications. When people stop them, weight can increase.”

Keeping up with physical activity and healthy eating remains important while taking GLP-1 drugs and is a key recommendation from many organizations. It can boost the benefits of medication, improve quality of life and help maintain weight loss. And these benefits can build on each other.

“I’ve had patients note that they no longer have a taste for sugar-sweetened beverages or alcohol after starting these medications. They find it easier to limit processed food intake and to control portions,” she said. “And as people begin to lose weight, they often find regular physical activity easier to do.”

It’s clear there’s a lot of interest in GLP-1 drugs. A recent KFF survey found that as many as 12% of people in the U.S. already take one, and that number is likely to keep growing. While we still have a lot to learn about their long-term risk and benefits, so far GLP-1 drugs have shown real potential for improving people’s health and well-being.

Dr. Graham A. Colditz leads prevention research at Siteman Cancer Center at Barnes-Jewish Hospital and WashU Medicine in St. Louis. Much of his work focuses on translating research findings into tools and tips that help people lower their risk of disease and improve their health — including the 8IGHT WAYS® to Prevent Cancer series.